2

Healing process:
Sometimes fluid can accumulate under the skin as the body heals from surgery. If it's not very painful or red, then it's probably not an emergency, but the surgeon should be notified.
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3

Possibly:
the weight gain may have thinned the skin and allowed it to become irritated more easily as well as put more pressure on it from the hernia. Need to see a surgeon now for evaluation and to prevent infection or involvement of the hernia itself.
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8

Protect it:
An unpopped blister represents a closed sterile environment. Yes on occasion one can become infected then it is time to open it, however the risk of infection in a dressed open wound is still higher than that of an intact blister. The blister will gradually resolve with time.
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9

See below:
The area needs time to heal so the best thing you can do is to keep the area away from irritation and reoccurring trauma. Place some antibiotic ointment on it and protect it with gauze or bandage.
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